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To‘plamlar ustida amallar: birlashma, kesishma va farq

Ma’ruzachi: Fayziyev M.

Reja

• To’plamlar ustida amallar
• To’plamlar birlashmasi
• To’plamlar kesishmasi
• To’plamlar ayirmasi
• Entity Frameworkda to’plamlar birlashmasi va kesishmasi

To‘plamlar ustida amallar
To’plamlar birlashmasi.
Ta’rif. Har qanday ikkita to‘plamning barcha elementlaridan, ularni takrorlamasdan, tuzilgan to‘plamga shu to‘plamlarning birlashmasi (yoki yig‘indisi) deb ataladi.
1-shakl
To’plamlar kesishmasi.
Ta’rif. Har qanday ikkita to‘plamning barcha umumiy elementlaridan tuzilgan to‘plamga to‘plamlarning kesishmasi (yoki ko‘paytmasi) deyiladi.
2-shakl
3-shakl

Entity Frameworkda to’plamlar birlashmasi

• Set Operator: Union
• The Union extension method requires two collections and returns a new collection that includes distinct elements from both the collections. Consider the following example.

• The Union extension method doesn't return the correct result for the collection of complex types. You need to implement IEqualityComparer interface in order to get the correct result from Union method.

• Implement IEqualityComparer interface for Student class as below:

• Now, you can pass above StudentComparer class in the Union extension method to get the correct result:

Query Syntax

• The Union operator is Not Supported in C# & VB.Net Query syntax. However, you can use Union method on query variable or wrap whole query into brackets and then call Union().
• The following figure shows how each set operators works on the collections:

To’plamlar kesishmasi

• Set Operator: Intersect
• The Intersect extension method requires two collections. It returns a new collection that includes common elements that exists in both the collection. Consider the following example.

• The Intersect extension method doesn't return the correct result for the collection of complex types. You need to implement IEqualityComparer interface in order to get the correct result from Intersect method.
• Implement IEqualityComparer interface for Student class as shown below:

• The Intersect operator is Not Supported in C# & VB.Net Query syntax. However, you can use the Intersect method on a query variable or wrap whole query into brackets and then call Intersect().
• The following figure shows how each set operators works on the collections:

Foydalanilgan adabiyotlar

• https://www.entityframeworktutorial.net/efcore/create-model-for-existing-database-in-ef-core.aspx
• https://www.tutorialsteacher.com/linq/linq-set-operators-union
• https://www.tutorialsteacher.com/linq/linq-set-operators-intersect

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